Ok here it is, it depends on what the PSI rating and GPM of the pump, and HP of the motor.
If I have my facts straight, some aircraft power packs (not just the pumps, but the pump and motor together) can put out up to 3,000 PSI at 2 GPM at around 2 HP. It appears that most piston pump heads are the best.
I don't know what your power packs put out, having the specs might help.
I am not 100% clear on "Why" larger size diameter cylinders were used. was it because the pump could not lift the car, or do the pump heads blow?
Regarding larger size diameter cylinders, I used to use 1.25" cylinders called "Chrome Jets" to the front of my 71 Monte Carlo. Using four batteries, stock coils at 5 turns, 48 volts, I could hop 4" with a Pesco. I don't remember the model number of the power pack, but it was bigger than the 777 and maybe bigger than the 280 Pescos. (we got then for $45.00 at Pallies).
Anyways, I have come across this question many times before, I keep thinking that the pumps these days are worn out and not as newer as the ones I used to use, this is why some cars need the larger diameter cylinders, because the pumps are too worn, or the relief valve needs to be adjusted correctly, or maybe even tweaked.
Hmm... I just remembered I did blow a pump head, but I fixed that and the pump still worked, not as good, but maybe I only got 3" after that. So maybe if I used larger diameter cylinders, or used an external relief valve, the pumps heads would have lasted?
But anyways, Pro-Hopper does make a larger cylinder, maybe these might work rather than getting larger aircraft cylinders or special made cylinders.
When I get the chance, I'll plumb different Pescos and Stratopower power packs to my Regal and post the updates on
www.squaredump.com as I have been wanting to do this for some time.
